1. Field of the Invention
The present invention relates to a wheel hub clutch assembly for automotive vehicles of the four-wheel drive type, and more particularly to an improvement of a wheel hub clutch assembly arranged to automatically couple and uncouple a wheel hub to and from a driveable axle so as to selectively provide four-wheel drive or two-wheel drive.
2. Description of the Prior Art
Such a wheel hub clutch assembly as described above comprises a cylindrical body provided therein with internal splining and attached to a wheel hub, an inner sleeve contained within the cylindrical body and fixedly mounted on a driveable axle, a clutch member provided thereon with external splining and splined to the inner sleeve so as to be maintained in a first position in which the external splining of the clutch member is disengaged from the internal splining of the body to uncouple the wheel hub from the axle and to be axially moved from the first position to a second position in which the external splining of the clutch member is engaged with the internal splining of the body to drivingly couple the wheel hub to the axle, a cam ring formed at one side thereof with a cam face and rotatably mounted on the inner sleeve, a cam follower arranged between the clutch member and the cam ring and splined to the inner sleeve to cooperate with the cam face of the cam ring to be axially moved to and from the clutch member in response to rotation of the inner sleeve, a return spring for loading the cam follower toward the cam face of the cam ring, means for connecting the cam follower with the clutch member, and means for applying the brake to the cam ring in response to rotation of the cam follower. For actual practice of the wheel hub clutch assembly, various tests and experiments have been conducted by the inventors. In these tests and experiments, it has been observed that damage of the splining teeth or meshing noises is caused by incomplete disengagement of the clutch member from the body in declutching operation of the assembly.